Inventory management system using event filters for wireless sensor network data

ABSTRACT

A wireless sensor node, WSN, tag and method for filtering sensor data obtained by the WSN. At least one event filter is applied to sensor data. The sensor data is based at least in part on motion of the WSN tag. The at least one event filter includes at least one filter parameter, and the at least one filter parameter includes a minimum amount of movement of the WSN tag within a predetermined time threshold.

CROSS-REFERENCE TO RELATED APPLICATION

This application is related to and claims priority to U.S. ProvisionalApplication Ser. No. 61/613,048, filed Mar. 20, 2012, entitled INVENTORYMANAGEMENT SYSTEM USING EVENT FILTERS FOR WIRELESS SENSOR NETWORK DATAand U.S. Provisional Application Ser. No. 61/613,333, filed Mar. 20,2012, entitled RETAIL ITEM MANAGEMENT USING WIRELESS SENSOR NETWORKS,the entirety of both of which are incorporated herein by reference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

n/a

FIELD OF THE INVENTION

The present invention relates generally to retail item management andmore specifically to using event filters for wireless sensor node datafor item management.

BACKGROUND OF THE INVENTION

In retail stores, items of high value and popularity are often promotedusing displays in special locations of high visibility inside the retailstore. These special locations often include ends of aisles or oncountertops inside particular departments at which consumers are likelyto interact with the special items. For various reasons, retailers areintensely interested in the level and nature of human activitysurrounding the special items, in particular, the physical handling ofthese items. One source of interest to retailers is the concern ofpotential theft of the item. Another aspect of interest to retailersdeals with how the handling of the item correlates with the presentationand offering of the item. For example, retailers may want to knowwhether the price and placement of the item, coupled with all of theinfluencing factors such as advertising, store lighting and store-widesales promotions have resulted in a net increase or decrease in theamount of physical attention that the retail demo item garners. This isparticularly true for certain high-value or high-interest items, orpromotional items which have special correlation with general storeperformance or sales of a particular store department.

Some retailers employ tethers such as wires and cables attached toretail items on display in order to protect specially displayed retailitems and collect motion data. For example, a security device may betethered to a retail item on display in which a wire or set of wiresconveys motion data of the item to a computer hidden under or inside thedisplay fixture surface. However, tethers are often unsightly, and makehandling of the tethered retail item awkward.

While point of sale (POS) data is readily available to retailers, it isdifficult to use POS data to determine whether item placement in a storeis good or bad. For example, reviewing POS data is often not a goodindicator of item placement since price has such a profound influence onthe decision to buy. The decision to investigate and the decision to buyare very different, i.e., these decisions are dependent on differentfactors. In other words, it is very difficult to measure how an item isbeing handled inside the retail store because this information isindependent of POS data. While video surveillance can be used in somecases to monitor customer behavior, it is difficult to implement in amanner which allows for automated determination of specific customerbehavior such as the handling of a given retail item. In general, suchimplementations of video surveillance technology are labor-intensive,complex, and expensive.

Another source of interest that a retailer might have in the directphysical handling of retail items within a store has to do withdeployment of sales associates. For example, retailers want their saleemployees to spend a relatively large amount of their time dealingface-to-face with the shopper who is most interested in the high-profileretail item on display. However, at the present time, the retailer mustrely upon high levels of staffing to assure that shoppers will have anopportunity to deal face-to-face with a store associate at the time ofthe buying decision. While using a large number of store associates onthe sales floor at any one time may increase the amount of face timestore employees have with shoppers, high-staffing levels have thedisadvantage of high labor costs and training.

SUMMARY OF THE INVENTION

The present invention advantageously provides a method and system forretail item management using wireless sensor nodes. In particular, eventfilters are applied to capture wireless sensor node data to determinehow items are being physically handled.

According to one embodiment, a method for filtering sensor data obtainedby the WSN is provided. At least one event filter is applied to sensordata. The sensor data is based at least in part on motion of the WSNtag. The at least one event filter includes at least one filterparameter, and the at least one filter parameter includes a minimumamount of movement of the WSN tag within a predetermined time threshold.

In accordance with another embodiment, a wireless sensor node, WSN, tagfor identifying handling events is provided in which the WSN tag isassociable with an item. At least one sensor is configured to generatesensor data based at least in part on motion of the WSN tag. A memory isconfigured to store at least one event filter and the sensor data. Aprocessor is configured to apply at least one event filter to the sensordata where the at least one event filter includes at least one filterparameter. The at least one filter parameter includes a minimum amountof movement of the WSN tag within a predetermined time threshold.

In accordance with still another embodiment, a method for identifyinghandling events of a wireless sensor node, WSN, tag associable with anitem is provided. Sensor data is received in which the sensor data isbased at least in part on motion of the WSN tag. At least one eventfilter is applied to the sensor data. A filter firing of the at leastone event filter is triggered based at least in part on the applying ofthe at least one event filter to the received sensor data. Adetermination is made as to whether a handling event occurred based atleast in part on the filter firing of the at least one event filterwhere the at least one event filter includes at least one filterparameter. The at least one filter parameter includes a minimum amountof movement of the WSN tag within a predetermined time threshold.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the present invention, and theattendant advantages and features thereof, will be more readilyunderstood by reference to the following detailed description whenconsidered in conjunction with the accompanying drawings wherein:

FIG. 1 is a diagram of an exemplary item management system in use orconstructed in accordance with the principles of the present invention;

FIG. 2 is a block diagram of an exemplary item management systemconstructed in accordance with the principles of the present invention;

FIG. 3 is a block diagram of an exemplary wireless sensor node tagconstructed in accordance with the principles of the present invention;

FIG. 4 is a flow chart of an exemplary event determination process inaccordance with the principles of the present invention;

FIG. 5 is a flow chart of an exemplary tag event process in accordancewith the principles of the present invention;

FIG. 6 is a flow chart of an exemplary analytics process in accordancewith the principles of the present invention;

FIG. 7 is a flow chart of an exemplary reporting process in accordancewith the principles of the present invention; and

FIG. 8 is a list of reportable and non-reportable wireless sensor node(WSN) tag state changes in accordance with the principles of the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

Before describing in detail exemplary embodiments that are in accordancewith the present invention, it is noted that the embodiments resideprimarily in combinations of apparatus components and processing stepsrelated to implementing a system and method for retail item managementusing filters applied to captured wireless sensor node data.Accordingly, the system and method components have been representedwhere appropriate by conventional symbols in the drawings, showing onlythose specific details that are pertinent to understanding theembodiments of the present invention so as not to obscure the disclosurewith details that will be readily apparent to those of ordinary skill inthe art having the benefit of the description herein. While, one or moreembodiments herein suggest co-location of apparatus components insidethe same housing, system, or site location, the invention is not limitedto such. Actual deployment of may involve greater distribution ofcomponents and functionality around and among different physicaldevices, some of which may be remotely accessible such as via theInternet or internal network, or a combination of these networks. Whileone or more embodiments described herein have been simplified for thesake of clarity, the instant invention may include more highlydistributed embodiments which involve the same general components andfunctionality.

As used herein, relational terms, such as “first” and “second,” “top”and “bottom,” and the like, may be used solely to distinguish one entityor element from another entity or element without necessarily requiringor implying any physical or logical relationship or order between suchentities or elements.

Referring now to the drawing figures in which like reference designatorsrefer to like elements there is shown in FIG. 1 an exemplary systemwireless sensor node (WSN) tag system constructed in accordance with theprinciples of the present invention and designated generally as “10.”System 10 includes one or more items 12 a to 12 n (collectively referredto as “item 12”), one or more WSN tags 14 a to 14 n (collectivelyreferred to as “WSN tag 14”) and one or more user devices 16(collectively referred to as “user device 16”). In particular, aconsumer is illustrated interacting with item 12 a in which WSN tag 14 asenses the motion and determines whether the motion should be reportedas described in detail with respect to FIG. 4. Furthermore, WSN tag 14 nmay sense motion of item 12 n falling to the floor but does not reportthe motion as the motion does not meet the event filter as described indetail with respect to FIG. 4. In other words, WSN tag is programmed toreport predetermined motion events that are important to the retailerbased on filter parameters, i.e., motion events indicating a consumer isinterest in item 12. Furthermore, a notification may be sent to userdevice 16 based on the motion sensed by WSN tag 14 a such that anemployee is able to increase face-to-face time with a consumer that isshowing actual interest in item 12 a.

FIG. 2 is a block diagram of system 10. System 10 includes item 12, WSNtag 14, user device 16, one or more WSN access points 18 (collectivelyreferred to as “WSN access point 18”), one or more Wi-Fi Access points20 (collectively referred to as “Wi-Fi access point”), one or morenetworks 22 (collectively referred to as “network 22”) and one or moreanalytics devices 24 (collectively referred to as “analytics device24”). Item 12 may be a retail item or article. In one embodiment, WSNtag 14 is approximately one-third the size of a standard business cardand is attached to item 12 being displayed and monitored. In particular,WSN tag 14 is removably affixed to item 12 via methods known in the artsuch as via pin/lock. WSN tag 14 is described in more detail in FIG. 3.

User device 16 may be a mobile device for use by an employee in whichthe mobile device receives alerts and/or reports generated by system 10.For example, user device 16 may be a Smartphone, tablet computer orpersonal digital assistant (PDA), among other mobile devices that canreceive and display alerts and/or reports generated by analytics device24 and/or WSN access point 18. In particular, user device 16 includestransceiver 26 for communicating with Wi-Fi access point 20, among otherdevices in system 10. User device 16 also includes display 28 fordisplaying a received alert or report to an employee operating userdevice 16.

WSN access point 18 includes transceiver 30 that provides communicationto and from WSN tag 14 in which WSN access point 18 is co-located withWSN tags 14 in the retail store, e.g., separated by no more than severalhundred feet to support short-range radio communication. WSN tags 14form a sub-network that can access and be accessed by the WSN accesspoint 18 in which WSN tags 14 may be governed by multi-layercommunications protocols such as IEEE 802.15.4 media access control withZigbee or 6LoWPAN for network management and message routing, amongother communication protocols designed to achieve the same functions ofthe above cited standard layers. WSN access point 18 may transmit on a“short path” directly to Wi-Fi access point 20 as is described in detailwith respect to FIG. 5. Transceiver 30 can be a separate transmitter andreceiver but are described herein as a “transceiver” for efficiency andease of understanding. System 10 may include additional WSN networkelements, such as repeater nodes (not shown), designed to extend thephysical range of the network communication, and to store and forwardmessages in cases where WSN tags 14 or other network nodes are asleepand unable to receive or transmit messages in real-time.

WSN access point 18 includes processor 32 that may be one or morecentral processing units (CPUs) for executing computer programinstructions stored in memory 34. WSN access point 18 includes memory 34for storing tag event module 36 for tracking and reporting tag statechanges and tag state change data 38 based on event data 67 receivedfrom WSN tag 14. In particular, WSN access point 18 stores and updatestag state change data 38 in order to track which WSN tags 14 are in newstates. For example, tag state change data 38 may include a linked listof the WSN tags 14 in system 10 and a “state changed” flag for each WSNtag 14 in a linked list, among other information related to the changedstate of WSN tag 14. For example, tag state change data 38 may includedate/time of the event that caused WSN tag 14 to change states, type ofstate and tag ID as described in more detail with respect to FIG. 8.When WSN tag 14 sends a new state report to WSN access point 18indicating WSN tag 14 is in a new state, WSN access point 18 records thedetails of WSN tag 14's new or changed state in the linked list, andsets the state changed flag to “1”. Upon the next request from analyticsdevice 24 for new WSN tag 14 states, WSN access point 18 uses the statechanged flag to determine which WSN tags 14 have experienced a statechange since the previous polling request from analytics device 24.

After sending the report of WSN tag 14 with new states to analyticsdevice 24, WSN access point 18 resets the state changed flag to “0”.Therefore, WSN access point 18 tracks WSN tag 14 state changes. If morethan one analytics device 24 polls WSN access point 18, WSN access point18 may assign a service requester identification (ID) number for eachsubscribing analytics device 24, and may maintain a separate statechanged flag for each of the subscribing analytics devices 24. Themanner in which WSN tag 14 updates state information with WSN accesspoint 18 inside the WSN, and in which WSN access point 18 updates stateinformation with external devices (LAN or WAN based), such as analyticsdevice 24, may be governed by web service based publisher/subscribertechniques. More particularly, RESTful web services utilizing hypertexttransfer protocol (“HTTP”) or constrained application protocol (“CoAP”)message transport functionality may be used, among other applicationsand web-service implementation technologies. Memory 34 may includenon-volatile and volatile memory. For example, non-volatile memory mayinclude a hard drive, memory stick, flash memory and others known in theart. While volatile memory may include random access memory and othersknown in the art. Wi-Fi access point 20 provides communication to andfrom user device 16.

Analytics device 24 polls access point 18 for tag state change data andgenerates reports based on the received tag state change data 38.Analytics device 24 includes transceiver 40, processor 42 and memory 44.Transceiver 40 provides communications to and from analytics device 24.For example, transceiver 40 transmits polling commands to WSN accesspoint 16 via network 22 and receives tag state change data 38 from WSNaccess point 16. Processor 42 may be one or more central processingunits (CPUs) for executing computer program instructions stored inmemory 44. Memory 44 may function substantially the same ascorresponding memory 30, with size and performance being adjusted basedon design need. Memory 44 includes reporting module 46, Analytics module48 and motion database 50. Reporting module 46 includes instructions,which when executed by processor 42, causes processor 42 to perform thereporting process discussed in detail with respect to FIG. 7. Analyticsmodule 48 includes instructions, which when executed by processor 42,causes processor 42 to perform the analytics process discussed in detailwith respect to FIG. 6. Motion database 50 stores tag state change data38 and reports associated with WSN tag 14 state changes, among other WSNtag 14 related information. Network 22 may be a wide area network (WAN)such as the Internet, local area network (LAN), Ethernet LAN, cellularcommunication network, public switched telephone network (PSTN), Wi-Finetwork, or combination of any of these network types, among otherprotocol based networks.

FIG. 3 illustrates an exemplary block diagram of WSN tag 14. WSN tag 14includes antenna 52, radio frequency (RF) matching sub-circuit 54,transceiver 56, motion sensor 58, power supply 60, processor 62 andmemory 63. Transceiver 56, processor 62 and memory 63 may functionsubstantially the same as corresponding analytics device 24 components,with size and performance being adjusted based on design needs. Inparticular, processor 62, i.e., tag processor, may run tag managementsoftware or firmware that is configured with filter firmware to filterthe sensor data based on the at least one event filter.

Transceiver 56, RF matching sub-circuit 54 (that may include a balunchip) and antenna 52 provide communications with WSN access point 18such as to transmit event data 67 to WSN access point 18. Motion sensor58 may be a contact sensor or three-axis accelerometer, among othermotion sensing devices.

Memory 63 stores event module 64 and event filters 66. Event module 64includes instructions, which when executed by processor 62, causesprocessor 62 to perform the event process discussed in detail withrespect to FIG. 4. Event filters 66 include one or more filterparameters corresponding to one or more filters that are used todetermine whether an event occurred. In particular, event filters 66include firmware instructions, e.g., executable programmatic codeinstructions stored in memory 63 and at least one filter parameter suchas formula coefficients, exponents and/or other formula required values.Event filters 66 may also include special data structures or groupingsof data elements designed to facilitate processing and communication ofdata sets. In other words event filter 66 takes as input raw sensor dataand processor as output as “decision” or declaration as to whether aparticular event has occurred in which event has special significance ismathematically defined in the details of event filter 66.

Event filter 66 may be downloaded from analytics device 24 via WSNaccess point 18 such that event filter 66 of WSN tag 14 may bedynamically updated or replaced. In particular, WSN tag 14 may havedifferent event filters 66. Memory 63 may also store event data 67associated with a tag event. Power supply 60 may be a battery such as acoin cell battery and power-supply sub-circuit. Alternatively, powersupply 60 may be an energy harvesting module. WSN tag 14 may alsoinclude a light emitting diodes (LEDs) and/or piezoelectric resonator(not shown) to generate a hearable audio signal. Memory 63 and processor62 may be co-located on a single microcontroller (“MCU”) chip. In oneembodiment, the sensor data may be processed directly without storage ofthe sensor data in memory 63. Alternatively, sensor data may be storedin memory 63.

WSN tag 14 may periodically wake to transmit a tag event or may operatein low power mode where only the radio and other control circuitry areactive in order to detect polling commands from WSN access point 18.Further, processor 62 of WSN tag 14 may wake up due to sensed motionfrom motion sensor 58. In other words, WSN tag 14 may “sleep” toconserve power until a condition occurs that causes WSN tag 14 to wakeup.

Alternatively, WSN tag 14 may be a “dumb” tag that reports all motionssensed by motion sensor 58 such that WSN tag 14 does not performfiltering or performs minimal filter, i.e., reports motion above apredetermined threshold. Analytics device 24 would perform the filtering(described in detail with respect to FIG. 4) of sensor data receivedfrom WSN tag 14, i.e., event module 64 and event filters 66 are storedin memory 44. WSN tag 14 would report raw data to analytics device 24for filtering. In other words, this centralized filtering approach helpssimplify WSN tag 14 design, thereby reducing WSN tag 14 cost. However,this centralized filtering approach may also increase network traffic aslarge amounts of raw data may be generated by numerous WSN tags 14inside the WSN such that the actual number of WSN tags 14 that may bedeployed in this approach is limited.

FIG. 4 illustrates an exemplary flow diagram of the event determinationprocess at WSN tag 14 in which WSN tag 14 is associated with an item IDof item 12. In particular, processor 62 may receive the event filters orfilter parameters via wireless message using over-the-air firmwareupgrading or re-programming techniques. In particular, the downloadingof event filters and/or filter parameters may or may not requirere-initialization or re-booting of WSN tag 14, i.e., processor 62,depending on the nature of the operating system software running onprocessor 62. In one embodiment, WSN tag 14 may receive event filtersfrom analytics device 24 after processor 62 has already been initializedand commenced normal operation, and in which WSN tag 14 processor'soperating system updates event filters 66 with the received filterparameters. Filter parameters or event filters, i.e., formulas and/orfunctions to process raw sensor data and declare tag events, of WSN tag14 may be dynamically updated or replaced at substantially any time dueto received filter parameters, filter firmware and an associated commandto update the event filter 66. Processor 62 determines whether tagmotion has occurred based at least in part on data received from motionsensor 58 (Block S100). For example, processor 62 determines tag motionoccurred if a predefined threshold is met. The threshold may be 3D basedthresholds such that 3D accelerometer data in X, Y and/or Z directionsis used to determine motion has occurred, i.e., the thresholds areminimum acceleration values, and the accelerometer reports accelerationdata to processor 62 which can be compared to the threshold. Ifprocessor 62 determines no tag motion has occurred, processor 62 repeatsthe determination of Block S100.

If processor 62 determines that tag motion has occurred or is stillcurrently occurring, processor 62 determines whether at least one eventfilter 66 is met (Block S102). Each event filter includes and is definedby a number of filter parameters or thresholds that must be met in orderto determine an event occurred. The event filters or filter parametersare designed to be implemented in WSN tag 14 having a small memorystorage capacity, yet be complex enough to capture the salientcharacteristics of item 12 handling. The types of event filtersimplemented by WSN tag 14 fall into at least two general categories:thin filtering filters and thick filtering filters. Thin filters areevent filters at WSN tag 14 that report simple events more often thanthick filters. Thick filters are event filters that report a smallernumber of complex events.

One type of event filter is a first event filter that corresponds tospecific filter parameters in which the first event filter is the leastcomputationally complex filter. When processor 62 applies the firstevent filter, processor 62 counts the number of movements X above apredefined threshold, e.g., acceleration value above a certainacceleration threshold value, in a predefined time Y, where X and Y arepositive values. In cases where the accelerometer sensor itself employsinternal filters of its own, movements X can correspond to one or morenumber of different types of motions sensed by motion sensor 14 such asa tap, translation above X, Y, or Z-translation acceleration threshold,tilting and torquing, among other motions that may be sensed by motionsensor 14. In more limited situations where sensor 58 has no internalfilter such that filtering is done on the raw sensor data after the rawsensor data is reported to processor 62 by sensor 58, the raw sensordata involves only limited data such as X, Y and Z-translationacceleration. In translational acceleration threshold filtering formotion in dimension X, if the value of X, e.g., 0.1 gravitational (“g”)force, is above the predefined threshold, processor 62 determinesmovement X has occurred. The first event filter may be expressed inequation form as:

F₁=[ΣX→θ]_(Y) where ΣX is the sum of movements X with accelerationvalues exceeding the acceleration threshold θ, and Y is the thresholdtime. For example, if the acceleration threshold is 0.2 g's and thereare five movements X of force greater than 0.2 g in five seconds, andthe time threshold value Y equals six seconds, then the filter result is“true” and the filter declares the event, i.e., filter satisfied” event.

In one embodiment, movements X may correspond to a complex combinationof one or more of the above listed different types of motions. Forexample, movements X may be tilting movements, i.e., X=T, in which thefirst event filter may be expressed as:

F₁=[Σ→θ]_(Y) where ΣT is the sum of tilting movements in any plane, θ isthe threshold value expressed, for example, in degrees relative to someorientation plane for ΣT, and Y is the threshold time. One possible setof filter parameters for the first event filter may be θ=5, T=30 degreesand Y=60 seconds in which five movements of greater than 30 degrees mustoccur within sixty seconds for the event filter to be met.

A more explicit way of expressing this filter, F₁, is to show that alltilting movements that are counted in the sum are above a predefinedtilt threshold T_(m), i.e., tilt angle. The first event filter with thepredefined tilt threshold T_(m) may be expressed as:F₁=[ΣT_((T>Tm))→θ]_(Y). The first event filter is a thin filter if X issmall and/or θ is small, and Y is large.

Another type of event filter is a second event filter that automaticallychanges filter parameters, i.e., is self adapting, based at least inpart on the number of events WSN tag 14 has reported to WSN access point18, i.e., number of times WSN tag 14 has fired. The second event filteris express as:

F₂=[ΣT→θ]_(Y) and θ=θ(ΣF)=m*ΣF where ΣF is the total number of times(since filter reset) that the filter has fired, and m is a constant. Inother words, the second event filter fires like the first event filterbut will not fire again (prior to reset) for a handling event of thesame intensity, but requires an increased handling intensity after eachfire, i.e., θ increases after each firing. The second event filteradvantageously allows system 10 to capture the first primary event orfiring, and then capture any increases in intensity of handling of item12, without flooding the sensor network communication channels, e.g.,network 22, with redundant reports of continued handling at the initialintensity.

Another type of self adapting event filter is a third event filter thatautomatically changes filters parameters based at least in part onfiring or events reported by WSN tag 14. The third event filter isexpressed as:

F₃=[ΣT→θ]_(Y); Y=Y(ΣF)=Y_(o)*[1+ΣF]^(k) where Y_(o) is the initial valueof the time threshold, and k is a constant. If k is small and positive(between 0 and 1, closer to 0), then Y increases slowly with each filterfiring. However if k is large (k>2), then Y increases very rapidly witheach filter firing. If k is negative, then the time limit Y isshortened, slowly or quickly, depending on the magnitude of k, aftereach filter firing event. The third event filter may be used whenretailer put more importance on the first firing event than motionoccurring over time. For example, the retailer may implement the thirdevent filter if it is very important to know the first time motionoccurs above the threshold, and less important, though not unimportant,to know that motion is occurring over time. In the case of retail itemmanagement, analytics device 24 may be notified as soon as a retail itemis handled above a certain threshold, e.g., 3 tilts in 25 seconds. Ifanother 3 tilts occurs in the next 25 seconds, the second event may notbe as interesting as the first event since analytics device 24 alreadyknows the item is being handled. However, retailers may want to know ifthe next 3 tilts occur within the next 10 seconds, not 25 seconds, inwhich constant m can be properly chosen such that the second filterfiring occurs due to a high intensity handling event.

Another event filter is a fourth event filter that tapers the “turningoff” of the filter to match real-world handling of item 12. For example,fourth event filter includes a filter counter that starts at 0, andincrements (+1) if motion above threshold 0 occurs. Anytime that thecounter is greater than 0, a timer t is running. If the timer t reachesa predefined time limit Y prior to another motion above threshold, thecounter is decremented (−1) and the timer is reset. If the counterreaches 0, the timer is reset but does not start again until there isanother motion event above threshold. However, if the filter counterreaches some threshold θ at any time, the filter is satisfied, i.e., theevent trigger filter firing and the event is reported.

Another event filter is a composite event filter that includes at leasttwo event filters of the same and/or different filter type. Onevariation of the composite event filter is a series composite filter inwhich firing of a first filter disables the first filter and enables thesecond filter in the series. Firing of the second filter disables thesecond filter and enables a third filter in the series, and so on untilthe final filter fires. After the final filter fires, the final filteris disabled and the first filter is enabled such that the processrepeats. For example, firing of first event filter (F₁) enables thesecond event filter (F₂) while also disabling the first event filter(F₁). For example, a consumer may pick up and handle an item causing atleast 5 motions X within 10 seconds such that the first event filterfires, i.e., is triggered, and then is disabled. The consumer maycontinue to handle the item but may start to intently examine the itemthereby causing higher intensity firings over the next 10 seconds suchthat the second filter fires causing a tag event to be reported.

A second variation of the composite event filter is a parallel compositefilter. In the parallel composite filter, at least two event filters aregrouped together in a set, and firing by one of the event filters in theset constitutes firing of the set. For example, the first event filter(F₁) and second event filter (F₂) may be grouped together in parallel inwhich firing of either filter constitutes firing of the set. Forexample, filter F₁ might be triggered after detection motion for Xseconds while a second filter might be triggered after motion isdetected for X+Y seconds from the initial motion. A consumer may pick upitem 12 and start intensely handling the item 12, i.e., inspects theitem from all angles, such that the second event filter that has timethreshold of 30 seconds is triggered after the first event filter with atime threshold of 10 seconds, with both time thresholds being based onthe same starting point in time. The tag event is then reported.

A third variation of the composite event filter is a series-parallelcomposite filter that includes at least three event filters in aseries/parallel configuration. For example, the first event filter, F1,may be in series with a set of parallel filters (F2, F3, F4) in whichthe set of filters are inactive until the first event filter fires.After the first event filters fires, the set of filters (F2, F3, F4) areactivated and the first event filter is deactivated. Firing of eitherF2, F3 or F4 will cause a report or event data 67 to be transmitted toWSN access point 18. For example, a consumer may pick up item 12,examine the item and put item 12 back down, thereby triggering firstevent filter which will disable the first event filter and enable theparallel set of filters. The consumer may then pick up item 12 for asecond time as if still trying to decide whether to purchase item 12 inwhich the handling of item 12 the second time around is more intense,i.e., the consumer lifts the item up in order examine under item 12. Theexamination causes the second event filter to trigger before the thirdand fourth event filters such that the event is reported and the set ofparallel event filters are disabled, the first event filter is enabled.The series/parallel filter set approach is suited to defining complexmotions of items which involve alternating acceleration andturning/tilting of items. For example, an initial translationalacceleration followed by a series of tilting changes may becharacteristic of item “pick up and examination” whereas a series ofrepeated (cyclical) translations and tilting my indicate examination ofan item by a group of two or more people. Additionally, aseries/parallel arrangement of filters based on infrequent butsignificant large in the X and Y directions but very frequent andsmaller accelerations in the Z direction may be indicative of a personwalking with an item in their possession.

Although the parallel, serial and composite event filters are describedwith reference to a single WSN tag 14, the invention is not limited tosuch. It is contemplated that the determination of the parallel, serialand composite triggering can be made by WSN access point 18 or analyticsdevice 24 using filters in those devices based on sensor data providedby multiple WSN tags 14 or based on the firing of a set of filters in asingle WSN tag 14. Furthermore, when a set of WSN tags 14, each with itsrespective internal series/parallel set of filters is employed tomonitor a collection of retail items 12, the filter events from one tagmay influence the activation and deactivation of filters or subsets offilters in other (adjacent) WSN tags 14. Such activation anddeactivation of filters in adjacent WSN tags 14 provides added utilityin monitoring the activity in a particular part of a retail store inwhich WSN tag 14 activity beyond a certain intensity, with numbers ofretail items 12 greater than a predefined small number, is not of greatbusiness importance since the store employee's response is notinfluenced by the additional event reporting. In other words, this“super-filter” may include filter sets from multiple WSN tags 14 and maythus have a single “event declaration” associated with it by the WSNaccess point or analytics device.

Another event filter is a learning mode event filter. The learning modeevent filter counts motion events and time intervals, and uses apre-programmed function form with regression analysis or rules todetermine its own parameters or selects from a list of pre-programmedparameters options (e.g., best-fit Y and θ values). Once filterparameters are selected or determined, the filter parameters are usedwhen WSN tag 14 is placed in normal activity mode. A variation of thelearning mode approach is when one of WSN tags 14 is instructed by WSNaccess point 18 or analytics device 24 to transmit raw motion sensor 58,i.e., cease all filtering. In particular, WSN tag 14 may receive acommand to report every slight movement (X>Xm for a small value of m) inwhich the analytics device 24 or other network entity uses the raw datato select an event filter and corresponding filter parameters that bestfit the raw data.

For example, the WSN tag set may include individual WSN tags 14 locatedat fixed positions along the walls, posts, shelf supports, and otherfixed points along the normal walkways inside the retail store. TheseWSN tags 14 may include proximity sensors (not shown) which detect whena person walks past or approaches inside a certain distance. During thesensor network training period, the tags are instructed to send alldetectable sensor readings, i.e., readings above noise level, to WSNaccess point 18 via the wireless network. During the same period oftime, employees are assigned to count the number of people walking upand down each aisle, either exhaustively or according to some statisticsbased sampling formula. Afterwards the raw proximity sensor data fromthe network of WSN tags 14 is compared with the eye-witness data todetermine which filters and filter parameter values can best fit theactual store traffic data. The fitted filters can then be usedsubsequently and trusted to yield accurate reports of store customertraffic without the need for on-site employee observation. Similarexamples could be used to determine which filters and filter parametersets best fit the “meaningful types of item handling” for theaccelerometer based filters described above.

Analytics device 24 and/or WSN access point 18 may then transmit theselected event filter and filter parameters to WSN tag 14 and instructWSN tag 14 to implement to selected event filter and leave the learningmode, i.e., enters normal activity mode using the selected event filter.Along with transmitting or stream raw data, WSN tag 14 may also tag orflag the raw data to indicate whether the handling of item 12 that isinitiating the stream is of interest to retailers based on predefinedparameters. Alternatively, the tagging or flagging may be done after thefact by reviewing video/closed circuit television (CCT) recordings ofthe sales floor and watching for item 12 handling. Time stamps or timeintervals for these events of interest are matched with the timestamps/intervals for the motion data, and WSN tag 14 raw data streamidentified and flagged.

The learning mode filter allows WSN tag 14 to off-load complex modelingto device(s) with greater computational capabilities, i.e., analyticsdevice 24, when the modeling is too complex to be handled by WSN tag 14.The learning mode filter may also be modified to include storage of theraw data from more than one WSN tags 14, sampled over time, in a cloudor local server based database for analysis. The motion database 50 ofraw data may be submitted to one or more of a number of different“learning machines” technologies such as fuzzy logic model developmentengines, neural network analysis, and various types of regressionanalyses.

Furthermore, WSN tag 14 may select its own filter parameters based uponthe level of network activity. For example, if WSN tag 14 tries todeliver a message from a previous event or firing and finds that thereis lots of activity on the network, as determined using collisionavoidance algorithms such as Carrier Sense Multiple Access withCollision Avoidance (CSMA-CA), WSN tag 14 may modify its own filterparameters to fire the filters more selectively or less often, i.e., mayswitch event filter types or may modify specific filter parameters. Thespecific type of self-censoring may be guided by external applicationsrunning in WSN access point 18 or analytics device 24, i.e., externallyimposed reporting criteria. For example, WSN tag 14 may be instructed toreport its “five most extreme” motion events in any 10 minute period,and then WSN tag 14 is left to iteratively modify its own filterparameters until, on average, WSN tag 14's filter reports meet theexternally imposed reporting frequency criterion.

Referring back to Block S102, if processor 62 determines an event filterhas not been met, processor 62 repeats the determination of Block S100.If processor 62 determines an event filter has been met, processor 62causes event data 67 associated with the event to be reported to WSNaccess point 18, i.e., the event filter fires (Block S104). Afterreporting the event, processor 62 performs the determination of BlockS100.

An exemplary tag event process is described with reference to FIG. 5.Processor 32 determines whether event data 67 associated with a tagevent has been received from WSN tag 14 (Block S106). Event data 67 mayinclude date/time of an event, tag ID, type of event and otherinformation related to event. For example, WSN access point 18 mayreceive a message indicating WSN tag 14 has detected tag event 70 (FIG.8) indicating “handling 256” event, as discussed in detail with respectto FIG. 8. If processor 32 determines event data 67 has not beenreceived from WSN tag 14, processor 32 repeats the determination ofBlock S106. If processor 32 determines event data 67 associated with atag event has been received from WSN tag 14, processor 32 causes tagstate change data 38 to be updated and stored in memory 34 (Block S108).For example, tag state change data 38 may include a linked list of WSNtags 14 that tracks which WSN tags 14 are in a new state and details ofthe handling event that was reported of by WSN tag 14.

Processor 32 determines whether to perform short path reporting (BlockS110). Short path reporting includes transmitting a reporting messagedirectly with any user device 16 on the Wi-Fi network without having togo to network 18 and analytic device 18, i.e., without having totransmit the reporting message to a cloud computing environment oroff-site software applications as an intermediary. Whether short pathreporting is performed is based at least in part on the nature of thereporting message and tolerability of the reporting message latency,among other factors. For example, short path reporting is not requiredfor some reports that are used for long-term analytics such asunderstanding how customers are interacting with items 12, for thepurpose of understanding the effects of product placement, price,packaging and other merchandising considerations. In one embodiment,soft reports may be included in the long-term analytics type reports andtherefore do not require short path reporting. Soft reports arediscussed in detail with respect to FIG. 7.

Other reports that are urgent and motivated by the need to respond to areal-time tag event such as a hard reporting event may be reported usingshort path reporting. For example, a potential theft of item 12 whichhas moved outside of a predetermined area may require reporting viashort path reporting that has less reporting delay due to less deviceintermediaries. Hard reporting events are described in detail withrespect to FIG. 7. If processor 32 determines to short path reporting isrequired, processor 32 causes transceiver 30 to transmit a short pathmessage to user device 16 via Wi-Fi access point 20. In order for WSNaccess point 18 to transmit to Wi-Fi access point 20, WSN access point18 may support at least two wireless protocols and may include twophysical radios such as ultra high frequency (“UHF”) radio, e.g.,industrial, scientific and medical (“ISM”) band or 868/915 MHz, forwireless sensor network communication and a 2.4 GHz radio forcommunication over the Wi-Fi network. Alternatively, WSN access point 18may use a common radio and protocol for communication within system 10or user device 16 may be part of the WSN network and adapted to receiveshort path messages. In some embodiments, user device 16 may itselffunction as WSN access point 18. In one example, when the retailemployee in possession of user device 16 enters a physical regionholding a set of WSN tags 14, those WSN tags 14 may detect and associatewith the WSN network created by the newly arrived access points providedby user device 16. This embodiment provides added utility since userdevice 16 can be in direct communication with all WSN tags 14 in thegeneral vicinity of the retail employee best able (in terms of physicalavailability and reaction time) to respond to local tag filter events.

Referring to the embodiment in which user device 16 and WSN access point18 are separate devices communicating with each other over a Wi-Finetwork, after transmitting the short path message, processor 32determines whether a polling message has been received from analyticsdevice 24 (Block S114). If a polling message has not been received,processor performs the determination of Block S106. Furthermore, WSNaccess point 18 may update the flags in tag state change data 38. Ifprocessor 32 determines a polling message has been received, processor32 causes transceiver to transmit event data 67 to analytics device 24(Block S116). After transmitting event data 67 to analytics device 24,processor 32 performs the determination of Block S106. Referring back toBlock S110, if short path reporting is not required, processor performsthe determination of Block S114. Alternatively, Blocks S110 and S112 maybe skipped or omitted based on design need. As mentioned above, theparticular details of the management of polling and response messagesmay be implemented using techniques such as RESTful web serving, CoAPbased messaging, and other open standards based techniques designed tosupport robust and RESTful (link-stateless) publisher/subscribercommunications.

An exemplary analytics process for tracking WSN tag 14 states andgenerating reports is described with reference to FIG. 6. Processor 42causes WSN access point 18 to be polled (Block S118). For example,analytics device 24 may transmit a polling command to WSN access point18 requesting tag state change data, i.e., WSN tags 14 that have changedstate from the last time the polling command was sent. Processor 42determines whether WSN access point 18 reports any WSN tag 14 statechanges in response to the polling command (Block S120). If processor 42determines that no WSN tag 14 state changes have occurred, processor 42returns to Block S118, i.e., analytics device 24 may periodically pollWSN access point 18 for WSN tag 14 state changes.

If processor 42 determines that at least one WSN tag 14 state change hasoccurred based on received tag state change data 38, processor 42generates at least two lists of WSN tags 14 that are in new states,i.e., tags 14 that have changed states (Block S122). In particular, onelist includes reportable WSN tag 14 states while the other list includesnon-reportable WSN tag 14 states. For example, non-reportable WSN tag 14states require entry into motion database 50 for establishing theexistence of WSN tags 14 and for further tracking, the existence of WSNtag 14, by itself, does not require generating a report or alert aspredefined by the retailer and/or system 10 administrator. In thesecases, WSN tag 14 state change is not significant or does not providenew useful data relating to consumer handling of item 12. Reportable WSNtag 14 state changes are predefined by the retailer and/or system 10administrator in which the state changes generate a report or alert,i.e., may transmit an alert to an employee's user interface device 16.Processor 42 causes the received WSN tag 14 state changes to be storedin motion database 50 (Block S124). Processor 42 generates report (BlockS126). For example, processor 42 performs the reporting process asdescribed in FIG. 7.

An exemplary reporting process for generating reports or alerts isdescribed with reference to FIG. 7. Processor 42 determines at least onerecipient associated with each event on the reportable list of WSN tag14 events based on reporting parameters (Block S128). For example, thereporting parameters may include the nature of the report, reportinghistory and/or incident escalation rules, staff member ID, availabilityof store employee, among other factors. In one embodiment, processor 42determines which recipient, i.e., store employee, should receive and acton a report/alert based on whether the store employee has received aprevious report within a predetermined time, whether the store employeehas acknowledged that a previous report has been acted on and/or spatiallocation of user device 16 associated with a user/employee with respectto the location of WSN tag 14 that generated the event. For example,since user devices 16 are part of the WSN, the location of user devices16 and WSN tag 14 may be determined based on spatial location methodssuch that processor 42 determines that a first employee is closer to WSNtag 14 than a second employee. In this case, the first employee receivesthe report/alert from analytics device 24.

WSN tag 14 may be located within a store or predetermined location inwhich WSN access point 18 may use the signal strength of messagetransmitted by WSN tag 14 to determine the location of WSN tag 14. Inother words, the received signal strength indicator (“RSSI”) at WSNaccess point 18 is used to determine WSN tag 14 location. In oneembodiment, the received signal strength may be averaged over time inorder to improve location determination accuracy. Further, triangulationand curve fitting techniques based on Fri's law or empirical adaptationsof Fri's law may then be used to determine the location of thetransmitting WSN tag 14.

One type of report/alert that may be generated are hard reports in whichthe hard reports are generated and send to a human or recipient systemthat causes immediate attention and response such as of urgent/criticalevent reporting. For example, a hard report may include an audioannouncement over the retail store loud speakers, or other audiblealarm. Another example of hard report may include emails and/or textmessages to user device 16 or other device that prompts an employee torespond.

Another type of report/alert that may be generated is a soft report inwhich the recipient of the report, e.g., employee, may examine thereport at a convenient time when the recipient is interested inconsidering events of a specific type or nature. In the case of retailitem management, the soft report may prompt an employee via user device16 to evoke a face-to-face customer service engagement with a consumerif the employee is in a position to respond to the report, i.e., isavailable or is not already helping another customer. After processor 42determines recipient(s) for each report, processor 42 cause transceiver40 to transmit the reports to respective recipients (Block S130). Forexample, the report may be communicated to a recipient via a loudspeaker, user device 16 and/or a desktop computer within the retailstore such as at customer service, among communicated to other devicescapable of receiving and displaying and/or announcing the report.Processor 42 causes the report event to be stored in motion database 50(Block S132).

FIG. 8 illustrates an exemplary list of tag state change data 38including both reportable and non-reportable WSN tag 14 state changes.In particular, list 68 may include a tag ID associated with the WSN tag14 that transmitted the event, tag state associated with the changedstate, date/time of event and whether the event is reportable ornon-reportable. For example, WSN tag event 70 is associated with“Handling 256” that indicates WSN tag 14 has come to rest afterpreviously being handled by a consumer. WSN tag event 72 is associatedwith “Handling 7” that indicates an intense handling characteristic of ashopper that is intently examining item 12. WSN tag event 74 correspondsto a “Battery Low” event that indicates WSN tag 14's battery voltage hasdropped below a critical value. WSN tag event 76 corresponds to an“Outside area” event that indicates WSN tag 14 has moved outside adesignated or allowed area, thereby indicating possible item 12 theft.WSN tag events 70-76 are reportable tab events. WSN tag events 78 and 80may correspond to other events that require recording but do not warranta report or alert. WSN tag events 82-86 correspond to “MIA” events thatindicate WSN tags 14 have not reported a status or “heart beat” to WSNaccess point 18 within a predetermined amount of time do not warrantreporting. Other handling events may be used in accordance with thepresent invention.

The present invention can be realized in hardware, software, or acombination of hardware and software. Any kind of computing system, orother apparatus adapted for carrying out the methods described herein,is suited to perform the functions described herein. Furthermore, theinvention may be realized using one or more radio technologies,modulation types, wireless protocols, reporting platforms (phone, table,pager, etc.), and may be incorporated in one or more types of messagingschema (codes or code systems used to define the messages between WSNtag 14 and WSN access point 18, or between access points 18/20 and othernetwork devices or entities on site or in a cloud computingenvironment). Furthermore, the functionality of analytics device 24 maybe implemented on a server on a retail store premise with WSN accesspoint 18, or may be included as part of WSN access point 18.

A typical combination of hardware and software could be a specialized orgeneral purpose computer system having one or more processing elementsand a computer program stored on a storage medium that, when loaded andexecuted, controls the computer system such that it carries out themethods described herein. The present invention can also be embedded ina computer program product, which comprises all the features enablingthe implementation of the methods described herein, and which, whenloaded in a computing system is able to carry out these methods. Storagemedium refers to any volatile or non-volatile storage device.Furthermore, system 10 is not limited to retail item management as theWSN infrastructure and software modules describe herein may be used toenable other applications such as employee time management, customerservice request and response, automated price updated and management,asset tracking, store traffic monitoring and area/department security,among other applications.

Computer program or application in the present context means anyexpression, in any language, code or notation, of a set of instructionsintended to cause a system having an information processing capabilityto perform a particular function either directly or after either or bothof the following a) conversion to another language, code or notation; b)reproduction in a different material form.

In addition, unless mention was made above to the contrary, it should benoted that all of the accompanying drawings are not to scale.Significantly, this invention can be embodied in other specific formswithout departing from the spirit or essential attributes thereof, andaccordingly, reference should be had to the following claims, ratherthan to the foregoing specification, as indicating the scope of theinvention.

What is claimed is:
 1. A method for filtering sensor data obtained by awireless sensor node, WSN, tag, the method comprising: applying, at theWSN tag, at least one event filter to the sensor data, the sensor databeing based at least in part on motion of the WSN tag, the at least oneevent filter including at least one filter parameter, the at least onefilter parameter including: a movement threshold that when met indicatesWSN tag movement has occurred, the at least one filter parameterdefining a minimum number of movements of the WSN tag within apredetermined time threshold, the minimum number of movementscorresponding to a handling event; and a counter initialized to apredefined value, the counter configured to increment if a number ofmovements of the WSN tag meets the movement threshold within apredefined time and decrement if the number of movements of the WSN tagfails to meet the movement threshold within the predefined time;determining, at the WSN tag and based on the application of the at leastone event filter to the sensor data, whether the at least one eventfilter is met; and in response to determining that the at least oneevent filter is met, transmitting, by the WSN tag, event data associatedwith the handling event.
 2. The method of claim 1, wherein the minimumnumber of movements includes a minimum number of tilting movements in atleast one plane.
 3. The method of claim 1, further comprising increasingthe movement threshold if WSN tag movement occurred.
 4. The method ofclaim 1, further comprising: resetting the counter to the predefinedvalue if the counter is decremented to be one of equal and less than thepredefined value.
 5. The method of claim 1, further comprising changingthe predetermined time threshold if the at least one event filter ismet.
 6. The method of claim 5, wherein the changing of the predeterminedtime threshold includes one of increasing and decreasing thepredetermined time threshold after the at least one event filter is met.7. The method of claim 1, wherein the at least one event filter includesat least a first event filter and second event filter, the first eventfilter being initially enabled and the second event filter beinginitially disabled; the method further including: enabling the secondevent filter if a filter firing of the first event filter occurs; anddisabling the first event filter if the filter firing of the first eventfilter occurs.
 8. The method of claim 1, further comprising a set ofevent filters including at least a first event filter and second eventfilter taken from the at least one event filter, the first event filterand second event filter being in a parallel configuration with eachother, both the first event filter and second event filters beinginitially enabled; and a filter firing of one of the first event filterand second event filter being a filter firing event for the set of eventfilters, a determination of whether a motion based event occurred beingbased at least in part on the filter firing event for the set of eventfilters.
 9. The method of claim 1, further comprising a set of eventfilters including at least a first event filter, second event filter andthird event filter taken from the at least one event filter, the firstevent filter being in a series configuration with the second eventfilter and third event filter, the second event filter being in aparallel configuration with the third event filter, the first eventfilter being initially enabled and the second and third event filtersbeing initially disabled; the method further including: enabling thesecond and third event filters if a filter firing of the first eventfilter occurs; and disabling the first event filter if the first filterfiring of the first event filter occurs.
 10. The method of claim 1,further comprising: receiving a command to enter a learning mode;generating at least one other filter parameter based at least in part onsensor data; and updating the at least one filter parameter based atleast in part on the generated at least one other filter parameter. 11.A wireless sensor node, WSN, tag for identifying handling events, theWSN tag being associable with an item, the WSN tag comprising: at leastone sensor, the at least one sensor configured to generate sensor databased at least in part on motion of the WSN tag; a memory, the memoryconfigured to store at least one event filter and the sensor data, theat least one event filter including at least one filter parameter, theat least one filter parameter including: a movement threshold that whenmet indicates WSN tag movement has occurred, the at least one filterparameter defining a minimum number of movements of the WSN tag within apredetermined time threshold, the minimum number of movementscorresponding to a handling event; and a counter initialized to apredefined value, the counter configured to increment if the number ofmovements of the WSN tag meets the movement threshold within apredefined time and decrement if the number of movements of the WSN tagfails to meet the movement threshold within the predefined time; and aprocessor, the processor configured to: apply at least one event filterto the sensor data; determine whether the at least one event filter ismet based on the application of the at least one event filter to thesensor data; and in response to determining that the at least one eventfilter is met, cause transmission of event data associated with thehandling event.
 12. The WSN tag of claim 11, wherein the processor isfurther configured to change the time threshold if the at least oneevent filter is met.
 13. The WSN tag of claim 11, wherein the processoris further configured to: reset the counter to the predefined value ifthe counter is decremented to be one of equal and less than thepredefined value.
 14. The WSN tag of claim 11, wherein applying at leastone event filter includes applying a set of event filters including atleast a first event filter, second event filter and third event filtertaken from the at least one event filter, the first event filter beingin a series configuration with the second event filter and third eventfilter, the second event filter and third event filter being in aparallel configuration with each other, the first event filter beinginitially enabled and the second and third event filters being initiallydisabled; the processor is further configured to: enable the second andthird event filters if a filter firing of the first event filter occurs;and disable the first event filter if the first filter firing of thefirst event filter occurs.
 15. A method for identifying handling eventsof a wireless sensor node, WSN, tag associable with an item, the methodcomprising: receiving sensor data, the sensor data being based at leastin part on motion of the WSN tag; applying at least one event filter tothe sensor data, the at least one event filter including: a movementthreshold that when met indicates WSN tag movement has occurred, the atleast one event filter defining a minimum number of movements of the WSNtag that are above a predefined time threshold for the at least oneevent filter to be met, the minimum number of movements corresponding toa predefined handling event; and a counter initialized to a predefinedvalue, the counter configured to increment if a number of movements ofthe WSN tag meets the movement threshold within a predefined time anddecrement if the number of movements of the WSN tag fails to meet themovement threshold within the predefined time; triggering a filterfiring of the at least one event filter if the received sensor datameets the at least one event filter; and determining the predefinedhandling event occurred based at least in part on the filter firing ofthe at least one event filter.
 16. The method of claim 15, furthercomprising a set of event filters including a first event filter, secondevent filter and third event filter taken from the at least one eventfilter, the first event filter being in a series configuration with thesecond event filter and third event filter, the second event filter andthird event filter being in a parallel configuration with each other,the first event filter being initially enabled and the second and thirdevent filters being initially disabled; the method further including: inresponse to a filter firing of the first event filter, enabling thesecond and third event filters; and in response to the filter firing ofthe first event filter, disabling the first event filter.
 17. The methodof claim 15, further comprising: generating at least one filterparameter based at least in part on the received sensor data; andtransmitting the generated at least one filter parameter to the WSN tagfor filter parameter updating.